But Downing Street said today that pay for defence and health staff had already been settled until the next financial year.

“The position is exactly as I set out last week, in that there are pay review bodies reporting, we’ve responded to some and we’ll respond to others in due course, as is normal,” the Prime Minister’s spokesman said.

“For 17/18 nurses, doctors, dentists and all armed forces have had and agreed 1% uplifts. Still to come are teachers, police, senior civil servants and police officers.”

Asked whether No 10 was ruling out revisiting the deals for 2017/18 in light of the general election result, the spokesman said: “These were the recommendations that were made for 17/18 and we’ve accepted them... These are the settlements for 17/18.”

The health service and defence pay review bodies are not due to report again until next spring.

Sources close to Mr Johnson said he "strongly believes" the Government can offer an increase in a "responsible way".

It follows an intervention yesterday from the Environment Secretary, Michael Gove, who said ministers should "listen to the pay review bodies" who recommend what wages should be in different professions.

Defence Secretary Michael Fallon, Transport Secretary Chris Grayling and Health Secretary Jeremy Hunt are also keen to see the cap relaxed, with Mr Hunt specifically calling for nurses to get a pay rise.